Process of preparing genistein

Abstract

The present invention provides a process of preparing the isoflavone genistein. Genistein is prepared by fermenting the bacteria Saccharopolyspora erythraea in the presence of a soy-based substrate. A process of recovering genistein from a bacterial fermentation medium using alkaline, organic solvent extraction is also provided.

What is claimed is: 
     
       1. A process of preparing genistein comprising fermenting Saccharopolyspora erythraea on a soy-based substrate and recovering the genistein. 
     
     
       2. The process of claim 1 wherein Saccharopolyspora erythraea is cultured for a period of time and under culture conditions sufficient for genistein formation. 
     
     
       3. The process of claim 2 wherein Saccharopolyspora erythraea is cultured at a temperature of from about 10° C. to about 45° C. in an aqueous, oxygenated medium having a pH value of from about 4.0 to about 9.0, which medium contains organic nutrients, vitamins and inorganic salts sufficient to maintain Saccharopolyspora erythraea viability. 
     
     
       4. The process of claim 3 wherein the temperature is from about 20° C. to about 30° C. and the medium has a pH value of from about 6.0 to about 8.0. 
     
     
       5. The process of claim 2 wherein the period of time is from about 20 hours to about 250 hours. 
     
     
       6. The process of claim 1 wherein genistein is recovered by extracting genistein from a fermentation medium in a water-immiscible organic solvent at a pH value of from about 8.0 to about 11.0. 
     
     
       7. The process of claim 6 wherein the pH value is from about 9.0 to about 10.0. 
     
     
       8. The process of claim 6 wherein the organic solvent is ethyl acetate. 
     
     
       9. A process of recovering genistein from a Saccharopolyspora erythraea fermentation medium comprising extracting genistein from the medium in an organic solvent at a pH value of from about 8.0 to about 11.0. 
     
     
       10. The process of claim 9 wherein the pH value is from about 9.0 to about 10.0. 
     
     
       11. The process of claim 9 wherein the organic solvent is ethyl acetate.